git.cworth.org Git - empires-server/blob - empires.js

   1 const express = require("express");
   2
   3 const app = express.Router();
   4
   5 const GameState = {
   6   JOIN:    1,
   7   REVEAL:  2,
   8   CAPTURE: 3,
   9   properties: {
  10     1: {name: "join"},
  11     2: {name: "reveal"},
  12     3: {name: "capture"}
  13   }
  14 };
  15
  16 /**
  17  * Shuffles array in place.
  18  * @param {Array} a items An array containing the items.
  19  */
  20 function shuffle(a) {
  21   if (a === undefined)
  22     return;
  23
  24   var j, x, i;
  25   for (i = a.length - 1; i > 0; i--) {
  26     j = Math.floor(Math.random() * (i + 1));
  27     x = a[i];
  28     a[i] = a[j];
  29     a[j] = x;
  30   }
  31 }
  32
  33 class Game {
  34   constructor() {
  35     this._spectators = [];
  36     this.next_spectator_id = 1;
  37     this._players = [];
  38     this.next_player_id = 1;
  39     this.characters_to_reveal = null;
  40     this.clients = [];
  41     this.next_client_id = 1;
  42     this.state = GameState.JOIN;
  43
  44     /* Send a comment to every connected client every 15 seconds. */
  45     setInterval(() => {this.broadcast_string(":");}, 15000);
  46   }
  47
  48   add_spectator(name, session_id) {
  49     /* Don't add another spectator that matches an existing session. */
  50     const existing = this._spectators.findIndex(
  51       spectator => spectator.session_id === session_id);
  52     if (existing >= 0)
  53       return existing.id;
  54
  55     const new_spectator = {id: this.next_spectator_id,
  56                            name: name,
  57                            session_id: session_id
  58                           };
  59     this._spectators.push(new_spectator);
  60     this.next_spectator_id++;
  61     this.broadcast_event("spectator-join", JSON.stringify(new_spectator));
  62
  63     return new_spectator.id;
  64   }
  65
  66   remove_spectator(id) {
  67     const index = this._spectators.findIndex(spectator => spectator.id === id);
  68     this._spectators.splice(index, 1);
  69
  70     this.broadcast_event("spectator-leave", `{"id": ${id}}`);
  71   }
  72
  73   add_player(name, character) {
  74     const new_player = {id: this.next_player_id,
  75                        name: name,
  76                        character: character,
  77                        captures: [],
  78                        };
  79     this._players.push(new_player);
  80     this.next_player_id++;
  81     /* The syntax here is using an anonymous function to create a new
  82       object from new_player with just the subset of fields that we
  83       want. */
  84     const player_data = JSON.stringify((({id, name}) => ({id, name}))(new_player));
  85     this.broadcast_event("player-join", player_data);
  86   }
  87
  88   remove_player(id) {
  89     const index = this._players.findIndex(player => player.id === id);
  90     this._players.splice(index, 1);
  91
  92     this.broadcast_event("player-leave", `{"id": ${id}}`);
  93   }
  94
  95   reset() {
  96     this._players = [];
  97     this.characters_to_reveal = null;
  98     this.next_player_id = 1;
  99
 100     this.change_state(GameState.JOIN);
 101
 102     this.broadcast_event("spectators", "{}");
 103     this.broadcast_event("players", "{}");
 104   }
 105
 106   reveal_next() {
 107     /* Don't try to reveal anything if we aren't in the reveal state. */
 108     if (this.state != GameState.REVEAL) {
 109       clearInterval(this.reveal_interval);
 110       return;
 111     }
 112
 113     if (this.reveal_index >= this.characters_to_reveal.length) {
 114       clearInterval(this.reveal_interval);
 115       this.broadcast_event("character-reveal", '{"character":""}');
 116       return;
 117     }
 118     const character = this.characters_to_reveal[this.reveal_index];
 119     this.reveal_index++;
 120     const character_data = JSON.stringify({"character":character});
 121     this.broadcast_event("character-reveal", character_data);
 122   }
 123
 124   reveal() {
 125     this.change_state(GameState.REVEAL);
 126
 127     if (this.characters_to_reveal === null) {
 128       this.characters_to_reveal = [];
 129       this.characters_to_reveal = this._players.reduce((characters, player) => {
 130         characters.push(player.character);
 131         return characters;
 132       }, []);
 133       shuffle(this.characters_to_reveal);
 134     }
 135
 136     this.reveal_index = 0;
 137
 138     this.reveal_interval = setInterval(this.reveal_next.bind(this), 3000);
 139   }
 140
 141   start() {
 142     this.change_state(GameState.CAPTURE);
 143   }
 144
 145   capture(captor_id, captee_id) {
 146     /* TODO: Fix to fail on already-captured players (or to move the
 147      * captured player from an old captor to a new—need to clarify in
 148      * the API specification which we want here. */
 149     let captor = this._players.find(player => player.id === captor_id);
 150     captor.captures.push(captee_id);
 151
 152     this.broadcast_event("capture", `{"captor": ${captor_id}, "captee": ${captee_id}}`);
 153   }
 154
 155   liberate(captee_id) {
 156     let captor = this._players.find(player => player.captures.includes(captee_id));
 157     captor.captures.splice(captor.captures.indexOf(captee_id), 1);
 158   }
 159
 160   restart() {
 161     for (const player of this._players) {
 162       player.captures = [];
 163     }
 164   }
 165
 166   get characters() {
 167     return this._players.map(player => player.character);
 168   }
 169
 170   get empires() {
 171     return this._players.map(player => ({id: player.id, captures: player.captures}));
 172   }
 173
 174   get spectators() {
 175     /* We return only "id" and "name" here (specifically not session_id!). */
 176     return this._spectators.map(spectator => ({
 177       id: spectator.id,
 178       name: spectator.name
 179     }));
 180   }
 181
 182   get players() {
 183     return this._players.map(player => ({id: player.id, name: player.name }));
 184   }
 185
 186   add_client(response) {
 187     const id = this.next_client_id;
 188     this.clients.push({id: id,
 189                        response: response});
 190     this.next_client_id++;
 191
 192     return id;
 193   }
 194
 195   remove_client(id) {
 196     this.clients = this.clients.filter(client => client.id !== id);
 197   }
 198
 199   /* Send a string to all clients */
 200   broadcast_string(str) {
 201     this.clients.forEach(client => client.response.write(str + '\n'));
 202   }
 203
 204   /* Send an event to all clients.
 205    *
 206    * An event has both a declared type and a separate data block.
 207    * It also ends with two newlines (to mark the end of the event).
 208    */
 209   broadcast_event(type, data) {
 210     this.broadcast_string(`event: ${type}\ndata: ${data}\n`);
 211   }
 212
 213   game_state_event_data(old_state, new_state) {
 214     var old_state_name;
 215     if (old_state)
 216       old_state_name = GameState.properties[old_state].name;
 217     else
 218       old_state_name = "none";
 219     const new_state_name = GameState.properties[new_state].name;
 220
 221     return `{"old_state":"${old_state_name}","new_state":"${new_state_name}"}`;
 222   }
 223
 224   /* Inform clients about a state change. */
 225   broadcast_state_change() {
 226     const event_data = this.game_state_event_data(this.old_state, this.state);
 227     this.broadcast_event("game-state", event_data);
 228   }
 229
 230   /* Change game state and broadcast the change to all clients. */
 231   change_state(state) {
 232     /* Do nothing if there is no actual change happening. */
 233     if (state === this.state)
 234       return;
 235
 236     this.old_state = this.state;
 237     this.state = state;
 238
 239     this.broadcast_state_change();
 240   }
 241 }
 242
 243 function handle_events(request, response) {
 244   const game = request.game;
 245   /* These headers will keep the connection open so we can stream events. */
 246   const headers = {
 247     "Content-type": "text/event-stream",
 248     "Connection": "keep-alive",
 249     "Cache-Control": "no-cache"
 250   };
 251   response.writeHead(200, headers);
 252
 253   /* Now that a client has connected, first we need to stream all of
 254    * the existing spectators and players (if any). */
 255   if (game._spectators.length > 0) {
 256     const spectators_json = JSON.stringify(game.spectators);
 257     const spectators_data = `event: spectators\ndata: ${spectators_json}\n\n`;
 258     response.write(spectators_data);
 259   }
 260
 261   if (game._players.length > 0) {
 262     const players_json = JSON.stringify(game.players);
 263     const players_data = `event: players\ndata: ${players_json}\n\n`;
 264     response.write(players_data);
 265   }
 266
 267   /* And we need to inform the client of the current game state.
 268    *
 269    * In fact, we need to cycle through each state transition from the
 270    * beginning so the client can see each.
 271    */
 272   var old_state = null;
 273   for (var state = GameState.JOIN; state <= game.state; state++) {
 274     var event_data = game.game_state_event_data(old_state, state);
 275     response.write("event: game-state\n" + "data: " + event_data + "\n\n");
 276     old_state = state;
 277   }
 278
 279   /* Add this new client to our list of clients. */
 280   const id = game.add_client(response);
 281
 282   /* And queue up cleanup to be triggered on client close. */
 283   request.on('close', () => {
 284     game.remove_client(id);
 285   });
 286 }
 287
 288 app.get('/', (request, response) => {
 289   if (! request.session.nickname)
 290     response.render('choose-nickname.html', { game_name: "Empires" });
 291   else
 292     response.render('empires-game.html');
 293 });
 294
 295 app.post('/spectator', (request, response) => {
 296   const game = request.game;
 297   var name = request.session.nickname;
 298
 299   /* If the request includes a name, that overrides the session nickname. */
 300   if (request.body.name)
 301     name = request.body.name;
 302
 303   const id = game.add_spectator(name, request.session.id);
 304   response.send(JSON.stringify(id));
 305 });
 306
 307 app.delete('/spectator/:id', (request, response) => {
 308   const game = request.game;
 309   game.remove_spectator(parseInt(request.params.id));
 310   response.send();
 311 });
 312
 313 app.post('/register', (request, response) => {
 314   const game = request.game;
 315   var name = request.session.nickname;;
 316
 317   /* If the request includes a name, that overrides the session nickname. */
 318   if (request.body.name)
 319     name = request.body.name;
 320
 321   game.add_player(name, request.body.character);
 322   response.send();
 323 });
 324
 325 app.post('/deregister/:id', (request, response) => {
 326   const game = request.game;
 327   game.remove_player(parseInt(request.params.id));
 328   response.send();
 329 });
 330
 331 app.post('/reveal', (request, response) => {
 332   const game = request.game;
 333   game.reveal();
 334   response.send();
 335 });
 336
 337 app.post('/start', (request, response) => {
 338   const game = request.game;
 339   game.start();
 340   response.send();
 341 });
 342
 343 app.post('/reset', (request, response) => {
 344   const game = request.game;
 345   game.reset();
 346   response.send();
 347 });
 348
 349 app.post('/capture/:captor/:captee', (request, response) => {
 350   const game = request.game;
 351   game.capture(parseInt(request.params.captor), parseInt(request.params.captee));
 352   response.send();
 353 });
 354
 355 app.post('/liberate/:id', (request, response) => {
 356   const game = request.game;
 357   game.liberate(parseInt(request.params.id));
 358   response.send();
 359 });
 360
 361 app.post('/restart', (request, response) => {
 362   const game = request.game;
 363   game.restart(parseInt(request.params.id));
 364     response.send();
 365 });
 366
 367 app.get('/characters', (request, response) => {
 368   const game = request.game;
 369   response.send(game.characters);
 370 });
 371
 372 app.get('/empires', (request, response) => {
 373   const game = request.game;
 374   response.send(game.empires);
 375 });
 376
 377 app.get('/spectators', (request, response) => {
 378   const game = request.game;
 379   response.send(game.spectators);
 380 });
 381
 382 app.get('/players', (request, response) => {
 383   const game = request.game;
 384   response.send(game.players);
 385 });
 386
 387 app.get('/events', handle_events);
 388
 389 exports.app = app;
 390 exports.name = "empires";
 391 exports.Game = Game;